Apparatus for directing fluids through a filter system

ABSTRACT

A fluid distribution system for directing fluids through a filter system. The fluid distribution system ensures proper distribution of fluids during the process of filtering as well as the process of washing a filter bed. The fluid distribution system may be used with numerous filter systems including but not limited to an upflow filter, a downflow filter, a combined upflow/downflow filter and/or multiple downflow filters connected in series.

FIELD OF THE INVENTION

[0001] The present invention includes one or more devices for directingfluids (i.e., a liquid and/or a gas) through a filter system forfiltering water and/or wastewater. The filter system includes but is notlimited to an upflow filter, a downflow filter, a filter system having acombined upflow filter and a downflow filter and/or a filter systemhaving multiple (i.e., more than one) downflow filters connected inseries.

BACKGROUND OF THE INVENTION

[0002] Various systems have been developed to filter water andwastewater. Typical filter systems include but are not limited to anupflow filter, a downflow filter, a combined upflow filter and adownflow filter and multiple downflow filters connected in series. Theterm upflow filter is given to a filter in which the liquid or influentto be filtered is directed in an upward path to remove impurities.Conversely, a downflow filter is a filter in which the influent isdirected in a downward path to remove impurities. In a combinedupflow/downflow filter, influent is directed upwardly through the upflowfilter to remove a predetermined percentage of the impurities in theinfluent and then the influent is directed downwardly through thedownflow filter to remove the remaining impurities to within anacceptable limit. In this type of system, it is common for the upflowfilter and downflow filter to include one or more layers of filter mediasupported by one or more gravel support layers. Gravel support layersare necessary for certain filter systems to prevent clogging of theunderdrain. For example, one common type of underdrain includes aplurality of underdrain blocks arranged in parallel rows across thebottom of the filter. The underdrain blocks act to direct and receivefluids including influent, effluent and air during operation of thefilter system. The underdrain blocks typically include multiple largeapertures through which the fluids are directed and received. Theapertures are of such a size that the filter media can pass therethroughand clog the underdrain block. This of course is disadvantageous. Onesolution has been the use of one or more gravel support layers tosupport the filter media. The gravel is larger than the openings in theunderdrain block and, therefore, does not pass therethrough.

[0003] However, gravel support layers have a number of disadvantages.Specifically, gravel support layers are expensive and time consuming toinstall. Further, gravel support layers consume a significant portion ofthe filter chamber thus reducing the filtering capacity of the bed.Also, gravel support layers are subject to being upset when uncontrolledair enters the filter bed due to improper installation of the air systemor operator error. Moreover, in filter beds using granular activatedcarbon such must occasionally be removed from the filter and placed in areactivation furnace. During removal of the granular activated carbon,the gravel becomes intermixed and is deposited in the reactivationfurnace. At the extreme temperatures necessary to reactivate thegranular activated carbon the gravel can explode damaging the furnace.

[0004] To overcome the disadvantages of gravel support layers, porousplates have been used with underdrain blocks. The porous plates obviatethe need for the gravel support layers because they prevent the filtermedia from passing through the apertures in the underdrain block.Typically, porous plates have been fastened directly to the underdrainblock with screws or bolts. This conventional means of securing theporous plate to the underdrain block has significant drawbacks. Theseconventional fasteners increase the cost of the system from both amaterials and labor stand point. Further, if the porous plate needs tobe replaced a laborer would be required to removal all of the numerousfasteners before such could be accomplished. Moreover, conventionalfasteners could damage the porous plate requiring its removal. Inaddition, a direct connection of the porous plate to the underdrainblock without sufficient offset would likely lead to maldistribution ofthe fluid.

[0005] To overcome the disadvantages of prior underdrain systemsincluding but not limited to the disadvantages attendant securing aporous plate to an underdrain block with conventional fasteners RobertsWater Technologies introduced the novel and unobvious INFINITY™continuous lateral underdrain. This underdrain is prior art to thesubject patent application as it was sold or offered for sale more thana year prior to the filing date of the subject patent application. Thisunderdrain is advertised on the World Wide Web atwww.robertsfiltergroup.com. While the INFINITY™ underdrain is asignificant improvement over previously developed underdrains, thepresent invention is yet a further substantial improvement over theINFINITY™ underdrain. Specifically, one aspect of the present inventionincludes a novel and unobvious means for permitting a porous plate to bereadily removed from a supporting structure allowing replacementthereof. A significant advantage to this aspect of the invention is thatthe porous plate can be removed from the supporting structure readilywithout damaging the major components of the underdrain.

[0006] Another significant disadvantage of prior developments is that anexisting underdrain could not be satisfactorily retrofitted with aporous plate thereby obviating the need for one or more gravel supportlayers. Further, prior developments lacked the ability to readilyretrofit numerous different types of underdrains with a porous plate tothereby obviate the need for one or more gravel support layers.

[0007] Prior fluid distribution systems included means for distributingair to a filter bed having one or more layers of media during washing ofthe filter bed. This is commonly referred to as air scouring. Airscouring has been determined to be an important process in cleaningfilter beds. A number of existing underdrain systems are designed suchthat liquids and gases flow through common conduits. Such underdrainsystems have significant drawbacks. Specifically, because of theconflict between the flow rates of liquids and gases, upper limits mustunnecessarily be imposed minimizing the flexibility in setting differentranges of flow rates for liquids and gases. Further, common dischargepassages for liquids and gases result in uneven discharge of the airbubbles resulting in undesirable maldistribution. To overcome thedisadvantages of prior underdrain systems including but not limited tothe disadvantages attendant common liquid and gas conduits, RobertsWater Technologies introduced the novel and unobvious ARIES® managed airsystems. This managed air system is advertised on the World Wide Web atwww.robertsfiltergroup.com. and disclosed in U.S. Pat. Nos. 5,535,202and 5,673,481. While the ARIES® managed air system is a significantimprovement over previously developed air scour systems, the presentinvention is yet a further substantial improvement as will be readilyrecognized by those skilled in the art.

[0008] Some previously known air scour systems have also suffered fromthe disadvantage of maldistribution owing to incomplete evacuation ofwater from the air conduit. The problem of incomplete evacuation ofwater is often experienced where the air conduit has not been installedcorrectly. One example, is an unlevel installation of the air conduit.In such circumstances, the exit or discharge openings on the low side ofthe air conduit often remain blocked by water preventing properdistribution of air to the filter bed to adequately clean the same.

[0009] Previously known combined air and liquid distribution systemsutilizing shared conduits have experienced uncontrolled releases of airwhich can lead to significant problems. Specifically, systems usingshared conduits are likely to experience rapid introduction of air orwater flow. This rapid introduction of flow can create a wave actionresulting in fluctuation of the interfaces which can expose the watermetering orifices to air flow resulting in gross maldistribution.

OBJECTS AND SUMMARY OF THE INVENTION

[0010] An object of the present invention is to provide a novel andunobvious fluid distribution system.

[0011] Another object of a preferred embodiment of the present inventionis to provide a fluid distribution system which obviates the need forone or more gravel support layers.

[0012] A further object of a preferred embodiment of the presentinvention is to provide a fluid distribution system which retains aporous plate without the use of conventional fasteners such as screwsand bolts.

[0013] Still a further object of a preferred embodiment of the presentinvention is to provide a fluid distribution system which permits readyremoval of a porous plate for replacement without damaging the majorcomponents of the fluid distribution system.

[0014] Yet still a further object of a preferred embodiment of thepresent invention is to provide a fluid distribution system which doesnot suffer from maldistribution of liquids and/or gases.

[0015] Another object of a preferred embodiment of the present inventionis to provide a fluid distribution system which permits upgrading anexisting underdrain system to allow removal of one or more gravelsupport layers without removing the existing underdrain structure.

[0016] A further object of a preferred embodiment of the presentinvention is to provide a fluid distribution system which can be readilyused in conjunction with numerous different exiting underdrains topermit removal of one or more gravel support layers.

[0017] Still another object of a preferred embodiment of the presentinvention is to provide a fluid distribution system which provides forseparate liquid and gas distribution conduits.

[0018] Still a further object of a preferred embodiment of the presentinvention is to provide a fluid distribution system that permits an airconduit to be readily attached to an underdrain.

[0019] Yet another object of the present invention is to provide a fluiddistribution system which includes an air conduit having means forfacilitating evacuation of water from the air conduit.

[0020] It must be understood that no one embodiment of the presentinvention need include all of the aforementioned objects of the presentinvention. Rather, a given embodiment may include one or none of theaforementioned objects. Accordingly, these objects are not to be used tolimit the scope of the claims of the present invention.

[0021] In summary, one embodiment of the present invention is anapparatus for use in a filter system for filtering water or wastewater.The apparatus includes an underdrain. The underdrain has at least onechamber. The apparatus further includes a porous plate and at least onesupport member for supporting the porous plate in fixed relationshiprelative to the at least one chamber. The support member includes aweakness point or other means for permitting ready removal of the porousplate. Another embodiment of the present invention is a method ofenhancing an existing underdrain of a filter system for filtering wateror wastewater. The method includes the steps of providing an existingunderdrain; providing an underdrain cap having a support member forsupporting or receiving a porous plate; securing the underdrain cap tothe existing underdrain; and, providing at least one porous plate toobviate the need for one or more media support layers.

[0022] A further embodiment of the present invention is an apparatus foruse in a filter system for filtering water or wastewater. The apparatusincludes an underdrain; an underdrain cap secured to the underdrain;and, an air distribution conduit detachably connected to the underdraincap. Still another embodiment of the present invention is an apparatusfor use in filter systems for filtering water or wastewater. Theapparatus includes at least one underdrain block and an air conduitdetachably connected to the underdrain block. Still another embodimentof the present invention is an apparatus for use in a filter system forfiltering water or wastewater. The apparatus includes an underdrain andan underdrain cap secured to the underdrain. The underdrain cap includesa recess or other means for receiving a porous plate.

[0023] Still a further embodiment of the present invention is anapparatus for use in a filter system for filtering water or wastewater.The apparatus includes at least one liquid distribution chamber and atleast one air distribution conduit. The apparatus further includes aporous plate. The at least one air distribution conduit includes an exitopening disposed such that air exits the air conduit below the porousplate.

[0024] Yet another embodiment of the present invention is an apparatusfor use in a filter system for filtering water or wastewater. Theapparatus includes at least one liquid distribution chamber and at leastone distribution conduit. The air distribution conduit includes aninternal flange or other means for facilitating evacuation of water fromthe air distribution conduit. Yet a further embodiment of the presentinvention is an apparatus for use in a filter system for filtering wateror wastewater. The apparatus includes at least one liquid distributionchamber and at least one air distribution conduit. The apparatus furtherincludes a porous plate. The liquid distribution chamber is disposedentirely below the porous plate. The at least one air distributionconduit includes upper and lower portions. The upper portion is locatedabove the porous plate while the lower portion is located below theporous plate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025]FIG. 1 is a cross-sectional view of a first preferred embodimentof the present invention depicting two of multiple possible variationsthereof.

[0026]FIG. 2 is a cross-sectional view of one of the two possiblevariations depicted in FIG. 1.

[0027]FIG. 3 is a cross-sectional view taken along lines 3-3 in FIG. 2.

[0028]FIG. 4 is a perspective view of the variation of the firstpreferred embodiment depicted on the left side of FIG. 1.

[0029]FIG. 5 is a cross-sectional view of two of multiple possiblevariations of the first preferred embodiment of the present inventionone of which is depicted in FIG. 1 the other of which is not depicted inany of the previous drawings.

[0030]FIG. 6 is a cross-sectional view of a second preferred embodimentof the present invention.

[0031]FIG. 7 is a cross-sectional view of a portion of the secondpreferred embodiment depicted in FIG. 6.

[0032]FIG. 8 is a cross-sectional view of one of the elements depictedin FIG. 7.

[0033]FIG. 9 is a cross-sectional view of one of the elements depictedin FIG. 7.

[0034]FIG. 10 is a cross-sectional view of one of multiple possiblevariations of the portion of the second preferred embodiment illustratedin FIG. 7.

[0035]FIG. 11 is a cross-sectional view of one of the elements depictedin FIG. 10.

[0036]FIG. 12 is a cross-sectional view of one of the elements depictedin FIG. 10.

[0037]FIG. 13 is a cross-sectional view of a third preferred embodimentof the present invention.

[0038]FIG. 14 is a cross-sectional view of a fourth preferred embodimentof the present invention.

[0039]FIG. 15 is a cross-sectional view of a fifth preferred embodimentof the present invention.

[0040]FIG. 16 is a cross-sectional view of a sixth preferred embodimentof the present invention.

[0041]FIG. 17 is a cross-sectional view of a seventh preferredembodiment of the present invention.

[0042]FIG. 18 is a cross-sectional view of an eighth preferredembodiment of the present invention.

[0043]FIG. 19 is a cross-sectional view of a ninth preferred embodimentof the present invention.

[0044]FIG. 20 is a cross-sectional view taken along a different sectionof the ninth preferred embodiment of the present invention.

[0045]FIG. 21 is a cross-sectional view of a tenth preferred embodimentof the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0046] The preferred forms of the invention will now be described withreference to FIGS. 1-21. The appended claims are not limited to thepreferred embodiments and no term used herein is to be given a meaningother than its ordinary meaning unless accompanied by a statement thatthe term “as used herein is defined as follows”.

FIGS. 1 through 4

[0047] Referring to FIGS. 1 through 4, a fluid distribution system A isdepicted. The fluid distribution system includes an existing underdrainB, a pair of underdrain caps C and D and a pair of air conduits E and F.An air supply connection G is secured to the air distribution conduit Ein a fluid tight manner. An air supply connection H is secured to theair distribution conduit F in a fluid tight manner.

[0048] The existing underdrain includes a plurality of rows ofunderdrain blocks which are positioned on or adjacent the bottom of thefilter. Only two rows are depicted in FIG. 1. The first row 2 of claytile underdrain blocks are disposed beneath the underdrain cap C. Therows are formed by multiple underdrain blocks positioned in end to endrelationship. As is conventional, the upper surface 4 of each of theclay tile underdrain blocks includes a plurality of openings (not shown)through which fluid can pass. Each underdrain block in the first row 2includes four (4) chambers or conduits 6, 8, 10 and 12. Openings (notshown) are provided in the underdrain blocks so that chamber 10communicates with chamber 6 and chamber 12 communicates with chamber 8.The second row 14 of clay tile underdrain blocks are configured in amanner similar to the underdrain blocks in the first row 2 and,therefore, these underdrain blocks will not be described in detail.

[0049] The underdrain cap C is secured and sealed to the clay tileunderdrain blocks via grout 16. However, it will be readily appreciatedthat any suitable material may be used to secure and seal the underdraincap C to the underdrain blocks including but not limited to elastomericsealants. Preferably, the underdrain cap C is extruded in continuouslengths from high impact corrosion resistant PVC. Hence, the underdraincap C preferably runs substantially the length of the row of underdrainblocks. However, it will be readily appreciated that the underdrain capC could be formed from any suitable material. Further, the underdraincap C may be sized such that multiple segments are positioned end to endto extend the substantially the length of the row of underdrain blocks.While the underdrain cap C is shown as running along (i.e., parallel to)the underdrain blocks, it will be readily appreciated that such could beoriented perpendicular to the underdrain blocks.

[0050] Referring to FIGS. 1 and 4, the underdrain cap C forms twoconduits or chambers 18 and 20. Chamber 18 communicates with chamber 6via the opening in the upper surface 4 of the underdrain blocks.Similarly, the chamber 20 communicates with the chamber 8 via theopenings in the upper surface 4 of the underdrain blocks. While twochambers are shown as being formed by the underdrain cap C, it will bereadily appreciated that the underdrain cap C may be configured suchthat one or more than two chambers are formed. The underdrain cap Cpreferably includes a pair of horizontal walls 22 and 24 extendingoutwardly from recessed portion 26. Walls 22 and 24 are provided withthe appropriate number of discharge openings or orifices 28 to assurethat the liquid flowing from the clay tile underdrain blocks is properlydistributed throughout the filter bed. When this embodiment of thepresent invention is used in an upflow filter, chambers 18 and 20 assurethat the influent to be filtered will be uniformly discharged into thefilter bed in the case of an upflow filter. Further, when used in anupflow filter these chambers assure that the backwash liquid which maybe either influent or filtered water will be uniformly discharged intothe filter bed. Similarly, when the present invention is used in adownflow filter, chambers 18 and 20 assure that the filtered water willbe uniformly collected and that the backwash liquid will be uniformlydischarged into the filter bed. This is a significant improvement ofprior devices which mounted a porous plate directly to an underdrainblock without any type of underdrain cap therebetween.

[0051] The underdrain cap C further includes a pair of verticallyoriented support members 30 and 32. Support member 30 includes a pair ofhorizontally extending elements 36 and 38. Elements 36 and 38 form arecess 40 for receiving a portion of porous plate 42. Verticallyoriented wall 43 supports the opposite end of porous plate 42.Similarly, support member 32 includes a pair of horizontally extendingelements 44 and 46. Elements 44 and 46 form a recess 48 for receiving aportion of porous plate 50. Vertically oriented wall 52 supports theopposite end of porous plate 50.

[0052] The air conduit E is snap fit onto the underdrain cap C.Specifically, the air conduit E has a pair of vertically extending walls54 and 56. Each of the walls 54 and 56 have a pair of recesses 58. Apair of walls 60 and 62 extend upwardly from the bottom of recess 26.The walls 60 and 62 each include a pair of protrusions 64 for engagingthe recesses formed in the corresponding walls of air conduit E. Thisconfiguration permits the air conduit to be readily snap fit onto theunderdrain cap C. It will be readily appreciated that various otherconfigurations could be used to snap fit the air conduit onto theunderdrain. In this regard, it is noted that while walls 60 and 62 aredepicted as being on the inside of the corresponding walls 54 and 56such orientation can be reversed. Air conduit E includes a pair ofshoulders 66 and 68. Shoulder 66 aids in securing porous plate 42 infixed relationship relative to the underdrain blocks. Similarly,shoulder 68 aids in securing porous plate 50 in fixed relationshiprelative to the underdrain blocks. It will be readily appreciated thatporous plates 42 and 50 are held in fixed relationship relative to theunderdrain block without the use of screws or bolts.

[0053] Referring to FIG. 3, porous plate 50 has a plurality of grooves70 formed therein. It should be noted that while FIG. 3 depicts porousplate 50, porous plate 42 is configured in an identical manner. Achannel 72 is disposed in each of the grooves 70. The channels 72 ensureproper distribution of air or other gas along the width of the porousplates 42 and 50. It will be noted that the ends of the porous plates 42and 50 adjacent the air conduit E are spaced from walls 54 and 56. Thisspacing permits air or other gas to enter the channels 72.

[0054] The preferred embodiment depicted in FIGS. 1 through 4 preventsthe mixing of gas or liquids in chambers 18 and 20.

[0055] Rebar hook anchor 74 is disposed in the grout between theunderdrain blocks to enhance securement of the underdrain caps C and D.

[0056] Referring to FIG. 2, underdrain cap D depicts one of manypossible variations to the underdrain cap C. Underdrain cap D is similarto underdrain cap C, therefore, only the differences will be explainedin detail. Vertically oriented walls 76 and 78 have horizontallyextending elements 80 and 82, respectively. Further, verticallyextending elements 84 and 86 are disposed adjacent elements 80 and 82,respectively. Elements 80 and 84 form a recess to receive one end ofporous plate 88. Similarly, elements 82 and 86 form a recess to receiveone end of the porous plate 90. Unlike porous plates 42 and 50, porousplates 88 and 90 directly abut the air conduit F. Metering orifices areprovided in the channels adjacent the air conduit F to permit air orother gas to enter the channels and subsequently pass through thecorresponding porous plate to the filter bed. It will be readilyappreciated that other types of openings other than metering orificesmay be used. Air conduit F has a different configuration from airconduit E. As will be appreciated by one of ordinary skill in the art,the air conduits may be configured in numerous different ways. Thedashed lines F′ illustrates one such possible modification.

FIG. 5

[0057] Referring to FIG. 5, a fluid distribution system I isillustrated. Fluid distribution system I is very similar to the fluiddistribution system A. Accordingly, only the differences will bedescribed. Specifically, air conduit J has a different configurationthan previously illustrated air conduits.

FIGS. 6 through 9

[0058] Referring to FIG. 6, a fluid distribution system K is depicted.The fluid distribution system K includes an existing underdrain L, apair of underdrain caps M and N and an air conduits O. An air supplyconnection (not shown) is secured to the air distribution conduit O in afluid tight manner to supply air or other gas to the air distributionconduit O. The existing underdrain L is as described in connection withthe fluid distribution system A.

[0059] The underdrain cap M is secured and sealed to the clay tileunderdrain blocks via grout 92. However, it will be readily appreciatedthat any suitable material may be used to secure and seal the underdraincap M to the underdrain blocks including but not limited to elasticsealants. Preferably, the underdrain cap M is extruded in continuouslengths from high impact corrosion resistant PVC. Hence, the underdraincap M preferably runs substantially the length of the row of underdrainblocks. However, it will be readily appreciated that the underdrain capM could be formed from any suitable material. Further, the underdraincap M may be sized such that multiple segments are positioned end to endto extend substantially the length of the row of underdrain blocks.

[0060] The underdrain cap M forms four conduits or chambers 94, 96, 98and 100. Chamber 94 communicates with the chambers in the underdrainblocks via the openings formed in the upper surface of the underdrainblocks. Chambers 96, 98 and 100 communicate with chamber 94 via aplurality of openings 101 formed in horizontally extending wall 102. Theunderdrain cap M includes a horizontal wall 104 which extendssubstantially parallel to wall 102. A plurality of openings 103 areformed in wall 104 to permit fluid to pass from chambers 96, 98 and 100upwardly through porous plate 106. A pair of elements 108 and 110 extendupwardly from wall 104 to support the mid-section of porous plate 106.End rails 112 and 114 extend along opposite sides of the wall 104.Porous plate support members 116 and 118 are connected to end rails 112and 114, respectively. Support members 116 and 118 are configured in asimilar manner. Accordingly, only support member 116 will be describedin detail.

[0061] Referring to FIGS. 7 through 9, support member 116 includes twoseparate elements 120 and 122. Element 120 includes a vertical segment124. The vertical segment 124 includes inner surface 126 and outersurface 128. A pair of members 130 and 132 extend inwardly from theinner surface 126. Members 130 and 132 form a recess for receiving aportion of porous plate 106 as is readily seen in FIG. 6. Members 134,136 and 138 extend outwardly from the outer surface 128. Members 134 and136 receive a portion of end rail 112. Member 138 has a pair ofprotrusions 140 and 142 as well as a weakness point 144. While weaknesspoint 144 is illustrated as a V-shaped notch, it will be readilyappreciated that the weakness point 144 can take many different forms.Further, it will be readily appreciated that the weakness point can beformed in a variety of different ways. Weakness point 144 allows removalof the porous plate 106 without damage to any major component of theunderdrain cap M. Specifically, one need only cut member 138 along theweakness point 144 to readily detach the porous plate support member 120from the porous plate 106. In this manner, the porous plate can bereadily replaced.

[0062] Element 122 is substantially L-shaped and receives a portion ofthe end rail 112 as seen in FIG. 7. Element 122 includes a pair ofv-shaped notches 146 and 148 which receive protrusions 140 and 142,respectively. Referring to FIGS. 10 through 12, an alternative form ofporous plate support member is illustrated. The porous plate supportmember 150 includes two separate elements 152 and 154. Element 152differs from element 120 in that the protrusions 156 and 158 as well asthe weakness point 160 are shaped differently. Element 154 differs fromelement 122 in that the recesses 162 and 164 are shaped differently.

[0063] Referring again to FIG. 6, the underdrain cap N is formed in asimilar manner to underdrain cap M and, therefore, will not be describedin detail. Air distribution conduit O is snapped onto pin 166. Pin 166is epoxied into grout 168 or other suitable material. Rebar hook anchor170 is provided to enhance securement of the underdrain caps M and N tothe underdrain blocks.

[0064] Air distribution conduit O includes a plurality of waterevacuation openings 172 and a plurality of air distribution orifices174. Internal flanges 176 and 178 facilitate the evacuation of waterfrom the air distribution conduit O.

[0065] Referring to FIG. 13, fluid distribution system P is similar tofluid distribution system K depicted in FIG. 6. Accordingly, only thedifferences will be explained in detail. System P includes an airconduit Q. Air conduit Q has a pin 180 formed as one piece therewith. Acorresponding thin female element 182 is epoxied into the grout 184 orother suitable material. The pin 180 is snapped into female element 182.

FIGS. 14 and 15

[0066] Referring to FIG. 14, a fluid distribution system R similar tofluid distribution system K is depicted. Accordingly, only thedifferences will be described in detail. Specifically, the fluiddistribution system R includes an air distribution conduit S. The airdistribution S conduit is secured to or alternatively formed as onepiece with elements 186 of porous plate support members 188. Air conduitS includes two internal flanges 185 and 187 which facilitate dischargeof water through the water evacuation openings 189. Similarly, FIG. 15depicts a fluid distribution system T that utilizes another alternativeair distribution conduit U. A plurality of laterals 190 extend outwardlyfrom the air distribution conduit U. The laterals 190 have a pluralityof openings (not shown) to discharge air into the filter bed during airscouring. Air distribution conduit U is secured in a similar manner toair distribution conduit S.

FIGS. 16 through 18

[0067] Referring to FIG. 16, fluid distribution system V is similar tothe fluid distribution system K with the exceptions that the air conduithas been omitted and the existing underdrain is a monolithic wheelerbottom. In addition, a toggle bolt 192 may be used with or in place ofthe rebar hook anchor 194. Further, porous plates 191 and 193 may beprovided with protrusions 196 or 198 to provide additional support forthe mid-section of the plates. Referring to FIG. 17, a fluiddistribution system W, similar to fluid distribution system V, is beinginstalled over an existing nozzle underdrain. Referring to FIG. 18, afluid distribution system X is mounted on a Trilateral air/waterunderdrain 199 via porous plate support members 200 and 202. Supportmembers 200 and 202 are connected to end rails 204 and 206,respectively. Preferably, end rails 204 and 206 are formed as one piecewith the Trilateral air/water underdrain 199. Support members 200 and202 are similar to support member 116 depicted in FIG. 6, and, thereforewill not be described in detail.

FIGS. 19 through 21

[0068] Referring to FIGS. 19 and 20, fluid distribution system Yincludes a one-piece underdrain 208, porous plates 210 and 212 and airdistribution conduit 214. Porous plates 210 and 212 are similar toporous plates 42 and 50. Underdrain 208 includes fluid chambers 216,218, 220 and 222. Chamber 216 communicates with chamber 222 via aplurality of openings 224 (only one of which is shown). Similarly,chamber 218 communicates with chamber 220 via a plurality of openings226 (only one of which is shown). Openings 228 are formed in upper wall230 to permit fluids to pass upwardly through porous plate 210. Supportwalls 232 and 234 extend upwardly from upper wall 230 to provideadditional support for porous plate 210. Openings 236 are formed inupper wall 238 to permit fluids to pass upwardly through porous plate212. Support walls 240 and 242 extend upwardly from upper wall 238 toprovide additional support for porous plate 212.

[0069] Underdrain 208 includes a plurality of air passageways 244uniformly spaced along its longitudinal axis. The left and right sidesof air passageways 244 are bounded by support walls 243 and 245,respectively. Support walls provide internal support for the underdrain208. Air passageways 244 are connected to air distribution conduit 214.An air supply source is connected to the air passageways 244 to directair to air conduit 214. Referring to FIG. 20, the underdrain includesvertical support walls 246. The vertical support walls 246 arepositioned intermediate adjacent air passageways 244 and provideadditional internal support.

[0070] Air conduit 214 is similar to air conduits E and F and,therefore, will not be described in detail. Dashed line 214′ illustratesanother possible variation of the air conduit. It should also be notedthat the air conduit could be formed as one piece with the underdrain orunderdrain cap.

[0071] Referring to FIG. 21, fluid distribution system Z is similar tofluid distribution system Y and, therefore, only the significantdifferences will be described. Air is supplied to air conduit 248 in amanner similar to that depicted in FIG. 1. Accordingly, the fluiddistribution system Z does not include internal air passageways that areutilized in fluid distribution system Y. The one-piece underdrainincludes support members 250 and 252 for supporting corresponding endsof the porous plates 254 and 256.

[0072] An air channel 258 is formed between support member 250 and wall260 of air conduit 248. Air channel 258 extends upwardly along the airconduit 248 and allows air discharged from the air conduit 248 viaopening 262 to be released into the filter bed during the step of airscouring the bed to clean the same. Similarly, an air channel 264 isformed between support member 252 and wall 266 of air conduit 248. Airchannel 264 extends upwardly along the air conduit 248 and allows airdischarged from the air conduit 248 via opening 268 to be released intothe filter bed during the step of air scouring the bed to clean thesame.

[0073] While this invention has been described as having preferreddesigns, it is understood that it is capable of further modifications,uses and/or adaptions of the invention following in general theprinciple of the invention and including such departures from thepresent invention as come within the known customary practice in the artto which the invention pertains and as may be applied to the centralfeatures hereinbefore set forth, and fall within the scope of theinvention and the limits of the appended claims.

We claim:
 1. An apparatus for use in a filter system for filtering wateror wastewater, said apparatus comprising: (a) an underdrain, saidunderdrain having at least one chamber; (b) a porous plate; and, (c) atleast one support arm for supporting said porous plate in fixedrelationship relative to said at least one chamber, said support armhaving means for permitting said porous plate to be readily removed fromsaid support arm.
 2. An apparatus as set forth in claim 1, furtherincluding: (a) first and second support arms for supporting said porousplate in fixed relationship relative to said at least one chamber, eachof said first and second support arms having a weakness point forpermitting said porous plate to be readily removed from said first andsecond support arms.
 3. An apparatus as set forth in claim 1, wherein:(a) said at least one support arm includes first and second sections,said first section being a separate piece from said second section, saidfirst section having a weakness point.
 4. An apparatus as set forth inclaim 1, wherein: (a) said underdrain includes an underdrain block andan underdrain cap, said underdrain cap being mounted on said underdrainblock; and, (b) said at least one support arm is operably connected tosaid underdrain cap.
 5. An apparatus as set forth in claim 4, wherein:(a) said underdrain cap includes at least one rail, said at least onesupport arm is connected to said at least one rail of said underdraincap.
 6. An apparatus as set forth in claim 5, wherein: (a) said at leastone support arm includes first and second sections, said first sectionis a separate piece from said second section, said first section has aweakness point formed therein, said first section further includes arecess for receiving a porous plate.
 7. An apparatus as set forth inclaim 6, wherein: (a) said first section includes first and secondhorizontally extending segments; said second section includes a firsthorizontally extending segment, said first horizontally extendingsegment of said second section is positioned between said first andsecond horizontally extending segments of said first section.
 8. Anapparatus as set forth in claim 7, wherein: (a) one of said first andsecond horizontally extending segments of said first section includesfirst and second protrusions; and, (b) said first horizontally extendingsegment of said second section has first and second recesses forreceiving said first and second protrusions, respectively.
 9. A methodof enhancing an existing underdrain of a filter system for filteringwater or wastewater, comprising the steps of: (a) providing an existingunderdrain of a filter system for filtering water or wastewater, theexisting underdrain including a first chamber; (b) providing anunderdrain cap having a least one support arm for receiving a porousplate; (c) securing the underdrain cap to the existing underdrain toform a second chamber which communicates with the first chamber; and,(d) providing at least one porous plate to obviate the need for one ormore media support layers.
 10. A method as recited in claim 9, includingthe further step of: (a) removing at least one gravel support layer fromthe filter system.
 11. A method as recited in claim 9, including thefurther step of: (a) snapping an air conduit onto said underdrain cap.12. A method as recited in claim 11, further including the step of: (a)forming an exit opening in the air conduit such that air exits the exitopening below the porous plate.
 13. An apparatus for use in a filtersystem for filtering water or wastewater, said apparatus comprising: (a)an underdrain; (b) an underdrain cap secured to said underdrain; and,(c) an air distribution conduit detachably connected to said underdraincap.
 14. An apparatus as set forth in claim 13, further including: (a)at least one porous plate; and, (b) said air distribution conduit havingat least one shoulder for securing said at least one porous plate tosaid underdrain.
 15. An apparatus as set forth in claim 14, wherein: (a)said underdrain includes an underdrain block, said underdrain cap issecured to said underdrain block.
 16. An apparatus as set forth in claim15, further including: first and second porous plates, said airdistribution conduit having first and second shoulders for securing saidfirst and second porous plates to said underdrain block.
 17. Anapparatus as set forth in claim 13, further including: (a) first andsecond support arms for supporting said porous plate in fixedrelationship relative to said at least one chamber, each of said firstand second support arms having a weakness point for permitting saidporous plate to be readily removed from said first and second supportarms.
 18. An apparatus as set forth in claim 17, wherein: (a) said firstand second support arms are operably connected to said underdrain cap.19. An apparatus as set forth in claim 18, wherein: (a) said first andsecond support arms each include first and second sections, said firstsection of each of said first and second support arms includes first andsecond horizontally extending segments; (b) said second section of eachof said first and second support arms includes a first horizontallyextending segment, said first horizontally extending segment of saidsecond section is positioned between said first and second horizontallyextending segments of said first section.
 20. An apparatus as set forthin claim 18, wherein: (a) said weakness point of each of said first andsecond support arms is formed in said first sections.
 21. An apparatusfor use in a filter system for filtering water or wastewater, saidapparatus comprising: (a) at least one underdrain block; and, (b) an airdistribution conduit detachably connected to said underdrain block. 22.An apparatus as set forth in claim 21, further including: (a) a firstporous plate, said air distribution conduit having a first shoulder forsecuring said porous plate to said underdrain block.
 23. An apparatus asset forth in claim 22, further including: (a) a second porous plate,said air distribution conduit having a second shoulder for securing saidsecond porous plate to said underdrain block.
 24. An apparatus as setforth in claim 22, wherein: (a) said air distribution conduit has afirst exit opening formed therein such that air exits the airdistribution conduit below said first porous plate.
 25. An apparatus asset forth in claim 24, wherein: said air distribution conduit has asecond exit opening formed therein such that air exits the airdistribution conduit below said second porous plate.
 26. An apparatus asset forth in claim 22, wherein: (a) said first porous plate has a firstgroove formed therein; and, (b) a first channel is positioned in saidfirst groove.
 27. An apparatus as set forth in claim 23, wherein: (a)said first porous plate has a first groove formed therein; (b) a firstchannel is positioned in said first groove of said first porous plate;(c) said second porous plate has a first groove formed therein; (d) afirst channel is positioned in said first groove of said second porousplate.
 28. An apparatus for use in a filter system for filtering wateror wastewater; said apparatus comprising: (a) an underdrain; and, (b) anunderdrain cap secured to said underdrain, at least one fluiddistribution chamber being formed between said underdrain and saidunderdrain cap, said underdrain cap having means for receiving at leastone porous plate.
 29. An apparatus as set forth in claim 28, wherein:(a) said underdrain includes an underdrain block.
 30. An apparatus asset forth in claim 28, further including: (a) an air distributionconduit snap fit onto said underdrain cap.
 31. An apparatus as set forthin claim 30, further including: (a) a porous plate, said airdistribution conduit having at least one shoulder for securing saidporous plate to said underdrain cap.
 32. An apparatus for use in afilter system for filtering water or wastewater; said apparatuscomprising: (a) at least one liquid distribution chamber; (b) at leastone air distribution conduit; (c) a porous plate, said at least oneliquid distribution chamber being disposed entirely below said porousplate; (d) at least a portion of said air distribution conduit extendsabove said porous plate; said air distribution conduit having at leastone exit opening where air exits the at least one air distributionconduit, said at least one exit opening is disposed below said porousplate.
 33. An apparatus for use in a filter system for filtering wateror wastewater; said apparatus comprising: (a) at least one liquiddistribution chamber; and, (b) at least one air distribution conduit,said air distribution conduit having upper and lower portions, said airdistribution conduit having internal flanges to permit liquid to beevacuated from the air distribution conduit at said lower portion. 34.An apparatus for use in a filter system for filtering water orwastewater; said apparatus comprising: (a) at least one liquiddistribution chamber; and, (b) at least one air distribution conduithaving upper and lower portions; (c) a porous plate, said at least oneliquid distribution chamber being disposed entirely below said porousplate; and, (d) said upper portion of said air distribution conduitbeing disposed above said porous plate, said lower portion of said airdistribution conduit being disposed below said porous plate.
 35. Anapparatus as set forth in claim 34, further including: (a) an underdrainblock, said liquid distribution chamber being formed in said underdrainblock.
 36. An apparatus as set forth in claim 35, further including: (a)an underdrain cap secured to said underdrain block.
 37. An apparatus asset forth in claim 36, wherein: (a) said air distribution conduit issnap fit to said underdrain cap.
 38. An apparatus as set forth in claim1, further including: first and second support arms for supporting saidporous plate in fixed relationship relative to said at least one liquiddistribution chamber, each of said first and second support arms havinga weakness point for permitting said porous plate to be readily removedfrom said first and second support arms.
 39. An apparatus for use in afilter system for filtering water or wastewater, said apparatuscomprising: (a) an underdrain, said underdrain having at least onechamber; (b) a porous plate; and, (c) at least one support member forsupporting said porous plate in fixed relationship relative to said atleast one chamber, said support member having a weakness point forpermitting said porous plate to be readily removed from said supportmember.